1. Field of the Invention
The present invention relates to an information input system for operating a machine using an input implement held in operator's hand, such as for example, an infrared remote controller for a television set, or to an information input system utilized for a menu operation or inputting operation of graphic or handwritten characters to a game instrument having a display or a personal computer. Further, it relates to an information input system suitable for control or manipulation of objects on the display.
2. Related Background Art
There has been used an infrared remote controller for control of a television set as a typical information input device, which emits modulated infrared-light coded according to input information by pushing a plurality of button switches provided on the controller. In such an information input system, machine operation or control can be performed according to the input information by receiving the above modulated infrared-light in an infrared-light detection unit attached to the television set and by decoding it.
However, in the above, conventional infrared remote controller, when adjusting an analog amount of sound volume or the like, the user must keep pushing the button switch until an optimum sound volume is obtained. This has caused a problem of poor operability. Also, if the television set incorporates a graphic user interface, such as a multimedia terminal, then it needs to input pointing information for menu operation and other interactive operations. In this case, a cruciform cursor key has been used for shifting of a cursor on the screen in general; however, this has caused the problem of bad workability as well.
Recently, there has been proposed a system structure adding a track ball to the controller as a pointing means instead of the cruciform cursor key for special uses such as video control and the like. With such a system structure, however, there have remained still other problems such as that the track ball is relatively expensive and does not work well.
There has been also proposed another type of cursor control system which inputs the pointing information using a light medium, for example, as disclosed in Japanese Patent Publication No. Hei 6-59807. In this system, a light source is built in the input implement for indication of its own position, and an image pickup element is provided on a machine side, so that the incident ray of light from the light source is received to detect the position of the input implement, whereby the cursor on the display is shifted. If the input implement is located close to the machine body, then the cursor will respond to relatively slight movement of the input implement.
However, as the distance between the input implement and the machine body becomes longer, the moving range of the input implement has to be made wider for scanning the cursor at will on the display. Accordingly, the above system also suffers from the problem that the workability of the input implement worsens as the input implement moves away from the machine body.
Furthermore, as the input implement moves away, the amount of light received by the image pickup element provided on the machine side is reduced and the noise of external light becomes relatively great. For this reason, there has arisen yet other problems such as that incorrect information could be input.